1. Field of the Invention
The present invention relates to shredders for destroying articles, such as documents, compact discs, etc.
2. Description of Related Art
Shredders are well known devices for destroying articles, such as paper, documents, compact discs (“CDs”), expired credit cards, etc. Typically, users purchase shredders to destroy sensitive information bearing articles, such as credit card statements with account information, documents containing company trade secrets, etc.
A common type of shredder has a shredder mechanism contained within a housing that is removably mounted atop a container. The shredder mechanism typically has a series of cutter elements that shred articles fed therein and discharge the shredded articles downwardly into the container. A common frustration of users of shredders is to feed misaligned articles into the feed throat, only to have the shredder jam after it has started to shred the papers.
The present invention endeavors to provide a shredder with a feature that determines misfeeds of the paper, particularly papers fed in at an angle that is likely to cause jamming, and then reminds the user to re-insert the paper, so that the paper is properly aligned, to prevent the shredder from jamming. The present invention determines misfeeds using an arrangement of sensors configured to sense the insertion of the paper. In particular, misfeeds are determined by the different time periods in which the sensors sense the articles that are being inserted, the thickness of the articles being inserted, and whether a predetermined number of sensors have sensed the articles that are being inserted.
The assignee of the present application, Fellowes, Inc., has developed thickness sensing technologies for shredders which may be used with the present invention. See U.S. Patent Application Publication Nos. 2006-0219827 A1, 2006-0054725 A1, 2007-0007373 A1 and 2007-0221767 A1, U.S. patent application Publication Ser. No. 11/867,260, and U.S. patent application Ser. No. 12/348,420, each of which is incorporated by reference herein in their entirety.